Amy Sanders is Kate's cousin. She is in a band and is not very responsible. She is practically an older version of Kate.

Kate and Amy seem to have a rocky relationship. In the episode Party Over Here, she didn't even know that it was Kate's birthday. When Amy brings out a cake, Kate is disappointed to find that it was a strawberry cake instead of a chocolate cake, there was no candles and no one sings "Happy Birthday." Kate is shown to be a lot nicer and mature than Amy.